REMARKABLE SPECIES OF ECrilllROTDS. 31 



the pharyngeal wall, except in the more conspicuous development 

 of the longitudinal muscle system and in the absence of the 

 trabecular layer. The typhlosohle-like ridge (fig. 35, ts.) in the 

 anterior part of oesophagus is superficially covered with an epi- 

 thelium, in which cell outlines are indistinct but which exhibits 

 nuclei arranged in a row (fig. 36, epL). The epithelium contains 

 a large number of small, yellowish brown spherules, either in a 

 scattered manner or in irregular and indefinite groups. The 

 spherules are probably the same as those contained in the wander- 

 ing cells. The main internal mass of the ridge is a transparent 

 chondroid substance, contained in which are a few cells and some 

 peculiar fibers. The former {c.t.c.) are without doubt of mesen- 

 chymatous nature ; they send forth into the ground-substance a 

 number of long and slender, fiber-like processes. The latter are 

 filaments of a considerable thickness ; they are irregularly wavy 

 and run in indefinite directions. Apparently they stand in no 

 direct connection with any of the cells, and their appearance 

 leads one to compare them with elastic fibers in the connective 

 tissue of the higher animals. From its structure the typhlosole- 

 like ridge can scarcely be assumed to be an organ of secretion 

 or of absorption. More probably it is an apparatus which may 

 aid in the mechanical crushing of the food mass taken in. 



The villi-like papillœ, the presence of which characterize 

 the inner surface of the crop, are of a very remarkable histo- 

 logical structure. They consist almost wholly of a syntitium, 

 evidently formed by fusion of the epithelial cells (fig. 38, epL). 

 The internal surface shows no ciliation. As seen on cross-sections, 

 there opens a large unicellular gland (gl.) nearly regularly in 

 the depression between the bases of every two papillœ. In this 



